Second quantization theory for many-particles stochastic dynamics on finite transport and storage capacity network

Nella tesi viene studiato il random walk di particelle non interagenti su network con capacità di trasporto e capienza dei nodi finite. L’argomento viene affrontato introducendo per il sistema un formalismo di seconda quantizzazione. Dopo avere dimostrato l'effettiva conservazione del numero totale di particelle e che per il sistema vale una relazione di bilancio dettagliato, vengono derivate le relazioni di Onsager per il caso di un network con capacità di trasporto finita. Infine, viene ricavata l'espressione esplicita della distribuzione stazionaria di probabilità per il caso di un network con capienza finita per nodo

Progetto 2004/2.2: Misure di concentrazione di gas in traccia e delle caratteristiche ottiche delle particelle di aerosol a Baia Terra Nova e Dôme C (DO3meCO2)

La comprensione dei meccanismi che determinano la concentrazione dei gas in traccia che maggiormente influenzano il sistema climatico, in particolare CO2, O3, CH4 e CO, è diventato un argomento di primaria importanza per la comunità scientifica che si occupa di questioni climatiche. Analoga importanza rivestono inoltre le ricerche miranti a valutare gli effetti che a scala regionale possono essere prodotti da altri componenti dell’atmosfera come gli aerosol e le nubi. Nel caso della CO2, la conoscenza della distribuzione della sua concentrazione alle alte latitudini è molto importante perché, trovandosi a grandissima distanza da regioni vegetate ed industriali, consente di valutare con accuratezza non solo il rateo medio annuo di crescita in condizioni background, ma anche le piccole fluttuazioni annuali determinate da fenomeni a grande scala. Questi studi e misure permettono inoltre la validazione dei modelli che descrivono il ciclo del carbonio su scala globale. Nel caso dell’ozono, il ruolo che tale gas riveste nella fotochimica della troposfera e in particolare nel determinarne la capacità ossidativa, il suo ruolo di tracciante dei processi di scambio stratosfera-troposfera e dei processi di trasporti di masse d’aria inquinate, rende fondamentale la conoscenza del rapporto di rimescolamento al suolo e dei suoi andamenti stagionali ed interannuali. A dispetto della loro bassa concentrazione nell’area antartica, gli aerosol possono rivestire un ruolo molto importante nel sistema climatico antartico, in particolare a causa dei bassi valori di elevazione solare e agli alti valori di albedo della superficie, condizioni che amplificano notevolmente gli effetti radiativi diretti degli aerosol. La scarsità di siti di misura in Antartide e nella zona del Mare di Ross, rendono le misure effettuate presso la stazione Mario Zucchelli (MZS), nell’abito del Programma Nazionale Ricerche in Antartide (PNRA), oltremodo preziose per offrire una copertura della zona costiera del continente. Nel presente report si descrivono le attività sperimentali condotte presso la stazione di Campo Icaro, lungo la costa del Mare di Ross, nel periodo 31 ottobre 2004 -17 febbraio 2005. Inoltre sono riportati i risultati preliminari dell’analisi dei dati raccolti durante tale campagna di misura

Interplay of coarsening, aging, and stress hardening impacting the creep behavior of a colloidal gel

We explore the dynamical and mechanical characteristics of an evolving gel in diffusing wave spectroscopy (DWS) and rheometry, aiming to assess how the gel evolution impacts the creep response of the system. Our gel is formed by inducing the aggregation of thermosensitive colloids by a variation in temperature. We find experimental evidence that the long time evolution of this gel is due to two distinct processes: A coarsening process that involves the incorporation of mobile particles into the network structure and an aging process that triggers intermittent rearrangement events. While coarsening is the main process governing the evolution of the elastic properties of the gel, aging is the process determining structural relaxation. The combination of both processes in addition to stress hardening governs the creep behavior of the gel, a creep behavior that is determined by three distinct contributions: an instantaneous elastic, a delayed elastic, and a loss contribution. The systematic investigation of these contributions in recovery experiments provides evidence that losses and delayed elastic storage have a common origin, both being due to intermittent local structural relaxation events

Bootstrapping and Collaboratively Enriching the Italian Domain WordNet through the WiKyoto Knowledge Editor

Enhancing the development of multilingual resources is of utmost importance for use in computer applications. The need of ever growing resources for effective multilingual content processing has given impulse to a radical change in the perspective of language resource (LR) creation, structuring, exploitation and maintenance. The Web has played a key role in this process: indeed the possibility to access growing amounts of structured and unstructured data as well as the ease of creating and sharing contents between distributed communities of users have strongly affected the methodologies and techniques to bootstrap, enrich and access LRs. From static knowledge bases usually created and maintained by groups of experts and tailored to the specific exploitation contexts, LRs have turned into dynamic repositories of linguistic knowledge. Their content is usually easily accessible over the Web and often exploited, aggregated and optimized on-the-fly by on-line information mining services. In this context, the adoption of standardized data formats to facilitate interoperability and data exchange is essential. Moreover, the creation and maintenance of these resources has taken great advantage from the possibility to harvest Web data in order to bootstrap or enrich them. Several new frameworks have been proposed to support access, search, integration and interoperability of "new generation" LRs. Wide distributed communities of Web users are more and more directly or indirectly involved in keeping language resources updated or in extending them. After a brief description of modern LRs, we focus our attention on two essential issues involving them: the need for standard formats that support interoperability in a distributed Web context and the possibility for the Web communities to collaboratively maintain and enrich these resources. In particular, we present the Italian WordNet (IWN) and its exploitation in the context of the KYOTO Project, as a real-world scenario where standardization, interlinking, enrichment as well as collaborative editing are put into practice. The KYOTO Project is a complex knowledge-driven environment built with the aim of enabling communities of users to mine information form textual documents, sharing the collected facts across cultures, languages and domains. The semantic ground supporting all the information mining tasks of KYOTO is constituted by the Multilingual Knowledge Base, composed by a collection of WordNets encoding language-specific lexical patterns for each language covered by KYOTO. All of them are mapped to the language-independent entities of the KYOTO Central Ontology. In the context of KYOTO, we describe the process followed to define WordNet-LMF (WN-LMF), the standard format tailored to represent lexical resources adhering to the lexical knowledge WordNet model, useful to easily integrate general and domain lexicons in KYOTO. We present the conversion of the IWN to the WN-LMF standard, as a necessary pre-requisite for IWN to be integrated in the Multilingual Knowledge Base. We expose a (semi)-automatic procedure which allows IWN to upgrade ILI connections to the last version available of the Princeton English WordNet, 3.0. We also consider the Species2000 SKOS thesaurus, a knowledge resource with a data structure different from WordNet: we present its conversion to WN-LMF. To enable the multilingual and multicultural community of KYOTO users to maintain and extend KYOTO knowledge resources, we introduce the Wikyoto Knowledge Editor: it is the Web-based wiki environment useful to navigate, collaboratively enrich the Multilingual Knowledge Base. We describe its Web interface by a practical use case concerning the extension of the Italian Domain WordNet

Screening of mutations in the CFTR gene in 1195 couples entering assisted reproduction technique programs

Genetic testing of the cystic fibrosis transmembrane conductance ( CFTR) gene is currently performed in couples undergoing assisted reproduction techniques ( ART), because of the high prevalence of healthy carriers in the population and the pathogenic relationship with congenital bilateral absence of vas deferens ( CBAVD). However, discordant data have been reported concerning the usefulness of this genetic test in couples with no family history of cystic fibrosis ( CF). In this study, we report the results of CFTR molecular screening in 1195 couples entering ART. Genetic testing was initially carried out in a single partner of each couple. CFTR mutations were detected in 55 subjects ( 4.6%), a percentage that overlaps with the one reported in the general population. However, significantly higher frequencies of were found in CBAVD individuals ( 37.5%) and in males with nonobstructive azoospermia ( 6.6%). The 5T allele was found in 78 patients ( 6.5%). This figure was again significantly different in males with nonobstructive-azoospermia ( 9.9%) and in those with CBAVD ( 100%). All together, 139 subjects ( 11.6%) had either a CFTR mutation or the 5T allele. Subsequent molecular analysis of their partners disclosed a CFTR mutation or 5T allele in nine cases ( 6.5%). However, none of these couples had CFTR alterations in both members, a CFTR mutation being invariably present in one partner and the 5T allele in the other. In order to improve genetic counselling of these couples, the TG-M470V-5T association was analyzed, and a statistically significant relationship between 12TG-V470 and CBAVD was detected

Device‐to‐Materials Pathway for Electron Traps Detection in Amorphous GeSe‐Based Selectors

The choice of the ideal material employed in selector devices is a tough task both from the theoretical and experimental side, especially due to the lack of a synergistic approach between techniques able to correlate specific material properties with device characteristics. Using a material-to-device multiscale technique, we propose a reliable protocol for an efficient characterization of the active traps in amorphous GeSe chalcogenide. The resulting trap maps trace back the specific features of materials responsible for the measured findings, and connect them to an atomistic description of the sample. Our metrological approach can be straightforwardly extended to other materials and devices, which is very beneficial for an efficient material-device co-design and the optimization of novel technologies

Photoluminescence Emission Induced by Localized States in Halide Passivated Colloidal Two-Dimensional WS2 Nanoflakes

Engineering physicochemical properties of two-dimensional transition metal dichalcogenide (2D-TMD) materials by surface manipulation is essential for their practical and large-scale application especially for colloidal 2D-TMDs that are plagued by the unintentional formation of structural defects during the synthetic procedure. However, the available methods to manage surface states of 2D-TMDs in solution-phase are still limited hampering the production of high quality colloidal 2D-TMD inks to be straightforwardly assembled into actual devices. Here, we demonstrate an efficient solution-phase strategy to passivate surface defect states of colloidally synthetized WS2 nanoflakes with halide ligands, resulting in the activation of the photoluminescence emission. Photophysical investigation and density functional theory calculations suggest that halide atoms enable the suppression of non-radiative recombination through the elimination deep gap trap states, and introduce localized states in the energy band structure from which excitons efficiently recombine. Halide passivated WS2 nanoflakes importantly preserve colloidal stability and photoluminescence emission after several weeks of storing in ambient atmosphere, corroborating the potential of our developed 2D-TMD inks

INTERMUSCULAR TWO-INCISION TECHNIQUE FOR S-ICD IMPLANTATION

Background The traditional technique for subcutaneous implantable cardioverter defibrillator (S-ICD) implantation, which involves three incisions and a subcutaneous pocket, is associated with possible complications, including inappropriate interventions. The aim of this prospective multicenter study was to evaluate the efficacy and safety of an alternative intermuscular two-incision technique for S-ICD implantation. Methods The study population included 36 consecutive patients (75% male, mean age 44 ± 12 years [range 20–69]) who underwent S-ICD implantation using the intermuscular two-incision technique. This technique avoids the superior parasternal incision for the lead placement and consists of creating an intermuscular pocket between the anterior surface of the serratus anterior and the posterior surface of the latissimus dorsi muscles instead of a subcutaneous pocket. Results All patients were successfully implanted in the absence of any procedure-related complications with a successful 65-J standard polarity defibrillation threshold testing, except in one, who received a second successful shock after pocket revision. During a mean follow-up of 10 months (range 3–30), no complications requiring surgical revision were observed. At device interrogation, stable sensing without interferences was observed in all patients. Two patients (5.5%) experienced appropriate and successful shock on ventricular fibrillation and in four patients (11%), a total of seven nonsustained self-terminated ventricular tachycardias were correctly detected. No inappropriate interventions were observed. Conclusions Our experience suggests that the two-incision intermuscular technique is a safe and efficacious alternative to the current technique for S-ICD implantation that may help reducing complications including inappropriate interventions and offer a better cosmetic outcome, especially in thin individuals